The following charts 32bit linux server with 64gb 100 puma aplications and rails 2.3.11. The first chart contains ruby 2.0, the second ruby 2.1 and the third ruby 2.1 with GC_HEAP_OLDOBJECT_LIMIT_FACTOR = 1.3.

I dispose doing tests with ruby with other values ​​for GC_HEAP_OLDOBJECT_LIMIT_FACTOR as 1.2, 1.3, 1.5, etc.

Performance for me was not affected. My test is to do something like:

1.upto (100_000) do | i |
MyModel.find (i)
end

In parallel check if the system crashes or is slow. With ruby 2.0 is slow, even with ruby 2.1 not the 1.3 FACTOR. To perform the above test have to make the change suggested by Eric Wong at #10009.